As elaborate and highly polarized cells, neurons of the central nervous system frequently extend their axons over extreme distances. Inherent in this phenomenon, neuronal processes encounter multiple varying extracellular microenvironments. beta-amyloid, glutamate, and neurotrophins are all examples of such microenvironmental exposures that may influence the function or even survival of neurons whose processes encounter them. Studies that examine the impact of these microenvironments on cellular processes and signaling cascades have in large part been hindered by the difficulty in replicating in vitro such microenvironmental exposures. Our lab has recently developed novel chambers using microfabrication and soft lithography techniques that can reliably and reproducibly simulate microenviroments encountered by CNS neurons. Further evidence shows that the neurites isolated are exclusively axons after nine days in vitro. This proposal is designed to further develop this novel multicompartment model for the study of microenvironmental influences over central neurons. In addition, the utility of this model will be examined in a study of the signaling cascades that mediate the phosphorylation of cAMP-responsive element binding protein (CREB) in response to axonally-restricted glutamate exposure. This proposal will test the hypothesis that axonal glutamate exposure induces CREB-phosphorylation via specific receptor-mediated initiation of intracellular signal transduction cascades. In particular, we will focus on potential calcium-mediated activation of Ras-ERK and CaM kinase pathways.